I have the same experience usually it ends as an error 12. The infinite save loop in my experience a save somewhere between an error 13 and a good save. The save file is 1-3% more in size than an error 13 save and the save game can sometimes be loaded. But I'm not confident on the game stability of those files.

My guess is that the invisible sim are textures and meshes failing to load into the cache.

Normally, the caches for riverview is located in the world cache directory. One is labeled objects the other is sim. I think those cache speaks for itself what it stored during gameplay. Deleting them in my case did not produce any problems only a very big lag and slow down during re-writing the cache. Also the dynamic cache feature that riverview uses has potential for writing saves. So sometimes you'll get an error 13 when the current size is full and does not seem to grow larger until your next game reload.

One suggestion I can think of is try going to the game directory where you installed your game, then go into the cache directory. Make a copy of the Sunset_valley.objectCache file and rename the copy to Riverview.objectCache. So you'll start with a cache 1Gb size and observe if you're still having these invisible sim problems.

I believe these minor glitches are probably the cause of the error 12, maybe not at first but given enough time they stack up and clutter to your cache that prevents you from doing anything afterwards. I will be making a list of the glitches I noticed prior to error 12s later. So that we can help each other look for a trend.

Edit:
Below is a partial list of glitches that I noticed  prior to receiving an Error 12:
1. Pathfinding issues for certain (not all) houses/lots when visiting. Sims gets stuck on something in front of the front door. Doorbell could not be activated as if nobody is home. Sims inside the house act as no one is ringing the doorbell if doorbell function activated.
2. Work and School performance drops and non active sims somehow does not go to work just standing around the house. This bug is not observed from all sims only some. There are sims in the same household and only one of them does not go to work. Also some unemployed sims does not seek jobs. They bum around the house. (NRaas Career mod not used)
3. Immovable urn / tombstones in community and residential lots of non active sims. Tombs and urns failed to be moved to the mausoleum.
4. Ghost aging bug. With prior releases of AM, Ghosts that returned to the netherworld still gets aging messages.
5. Missing inventory. So far with playable ghosts, some of them is missing their tombstones in their inventory and lets them live forever as elders.
6. Stuck sims on community lots. Somehow AM's no community swarm seems to fix this problem most of the time. It's often observed with overstuffed town population. They still somehow swarm on the bistro or theater and still get stuck with the no community swarm settings on but only on rare occasion.
7. Townie bug. With the Unified billing on, some non active families cannot afford to pay for their houses with their income even if all their careers are maxed. And somehow in their townie state, they get lost or disappear from the homeless list and reappear sometime later unaged. Some loses traits other loses their body mesh (invisible sim bug).
8. Another townie bug. In some rare occasion the game generates incomplete townies. The game either clone missing townie sims or creates ones without traits or favorites and sometimes both cloned and no personality.
9. Another rare occurrence, the game bypasses AM's storymode controls and mixes up unrelated household members as it normally does. And sometimes it moves out families from the neighborhood. It was weird that with AM and IS installed, there was a mass move out of the town residents leaving only 3 small non active family in town, even townies moved out. That was the last time I used IS. (note that IS and AM had the no move out option turned on. But AM story driver was active, IS story driver inactive)
So far these is what I can remember, I'll be adding if I could remember some more or encounter new ones.  

Also as a trial, I will be testing on using first the "fixall" command every 2am game time as a temporary cleanup process much the same as the games 12am and 5am cleanup process and see if error 12s can be reduced. The next step will try "resetallwants" if fixall does not work.

Edit 10/16: Work pusher does not work on sims who aren't going to work. Resetsim does work on them. These sims somehow have path finding issues. I watched one sim leaving the house to go to the carpool, instead of riding the car, she went into the garage and got stuck there.

Don't blame them, I'm very sure that they are just contracted telemarketers (call centers) that EA hired to do marketing and customer support and limited connection to EA itself. Basically they do not have any technical knowledge. They only have manuals and pre-made knowledge base answers provided to them for them to respond to customers. It may surprise you that some of them are as far as India or the Philippines. Worse yet the one answering your email may sometimes be a computer programmed to send out specific email responses based on keywords.

With regards to the patch, That's something you can believe him. Only the patch not exactly the repair part. Since World Adventures will be released next month there is really a patch included there though it may still be the v1.4 patch. Either way, error 12 and 13 will not be our only problem next month. Knowing the Sims 2 track record, we'll have new things to worry about. (Pray hard, cross all your fingers (including toes), knock on all the wooden things you see, and etc... that the last statement isn't true)

EDIT:
I posted this on the Official TS3 forums, I think this is the trend we'll be expecting from further expansions from the game:
This is the trend I see:
TS1 bug level : zero to minimal. The patches are few and rare for the whole series.
TS2 bug level : Minimal to Moderate. There are many bugs in every EP but they are still playable.
TS3 bug level : Moderate to Severe. Just the base game will foretell what to expect.
TS4 bug level : Probably unplayable.
I added the TS4 since there were some people who had nothing to do but speculate on something still far away and their ideas may be obsolete & forgotten in a couple of years or months.

EDIT 10/19
With stuck and work/school skipping bums, resetworld or resetsim does not always work. It seems they still skip work/school the next day. Also forcing them to go to work one household at a time is tedious but it works however, 1/3 of the way switching household to household also causes error 13s. I think something hardcored in the game that causes these bums to stop working to prevent error 13s, maybe an ingame failsafe. It is probably what's bypassing the NRaas Workpusher mod from working right. With the AM story driver the results are the same. Unemployed sims remains unemployed and employed non active sims just keep skipping work and losing jon performance. I tracked around 10/32 employed sims going to work, 31 sims are left unemployed, all kids skipping school.

That's a good suggestion. Though a word of warning, messing with the family ties can also break the game. As there are rare instances that some sims are broken. But do keep an observant eye when experimenting on stuff, keep backups so you have a returning point to go back to.

Edit: I did try to re-instate lost and broken family ties and got really messed up with some broken sims. I ended up having a loop where the great grandchild became the parent of the great grandparent and loops back to a full circle, the type you find on a sci-fi time travel paradox movie. I have to reload an old save after that. I am not advising against modifying the family tree, just take precautions.

10/15 Update:
One thing I notice before getting an error 12, is that some sims does not go to work and keep getting demoted. Even if they are already established with high positions. There also some sims that are non player user imported sims/households to the town that does not go find a job. I'm not sure if they are stuck or corrupted since changing households to these sims seemed to take 2x-4x longer to load the houses than the ones that does not have problems. Even houses that are overstuffed and very large loads faster than these problematic households. I'm going to try a work pusher mod and see if the error 12 instance would be reduced.

I haven't tried those mods. It seems these are not intrusive mods but I'm not sure if they are memory resident mods (sorry my programming and computer technology skills are outdated since the release of Pentium 1) Maybe reading the comments from these mods would give you ideas if you are experiencing the same problems with the mod as with other players who used it.

For unmovable graves, normally I nuke them with the Awesomemod and do the fixall command. Moving them into the mausoleum would be a more wiser choice since deleting it may not really remove possibilities that the sim becomes bugged or already bugged to begin with. It just removes the grave not the sim description. What I found is the Awesomemod's Destroyall... command does remove the sim descriptions, the NRaas SC sometimes does but not always in my case.

I'm not yet sure what causes this problem. But after using the S3RC, there is no improvement for the Error problems. Yet there is a random interaction that causes it. What I can identify is that certain sims does not respond well with hacks and mods. Some sims go crazy when the sim selector is used. Some sims gets bugged when the NRaas SC is used, weird is that Eric Darling and the Remingtons from Riverview shows up on the NRaas SC list even when they are still in their graves and their skin tone is black.

I have been re-purging my town last night and observing. I have restored the non-S3RC'd save file to wait if someone can come up with a tomb respawner mod for deleted tombstones. I figured that even with an empty town the game still bugs and I want to verify if the problem lies with the dead sims that are still encoded within the save game.  What I believe is that I may have used a conflicting mod in the past or a CC that was bypassed by the game and saved.

While bloating up my neighborhood in the past week, I noted that some sims that are being shared online are bugged I'm sure they are missing some CCs (which I do not need) when I installed them, normally, they the missing CCs will default to EAxis defaults but instead they cause CTD and weird stuffs. So it may be that in my earlier gameplay, the CCs were not that many and probably still in development filled with bugs that somehow gets saved and just remained with each successive save or worse yet, it could have acquired more bugs along the course of normal gameplay, which is being prevalent and persistent now.

I'm also having the same problem last night. I have started to purge the town and bit by bit to see what is causing it.

Just a recommendation, If you haven't tried to re-install the game and play your last save game vanilla (no update, no mods and no custom content and store items) now would be the best time to try.

Re-verified the bloated town issue with regards to Error 12. The Error is not based on sims or objects, removing everything on the neighborhood, the error does not go away. Resetworld or any command does not fix it. I suspect there is a corruption within the cache that causes the error 12.

Also having duplicate sims seems to make the error appear twice as fast. I may be mistaken but everytime I add Indie Stone or the NRaas Story Progression Driver, some family in the bin gets cloned into the game. I am aware of the immigration function of both mods and it is set not to immigrate. I make no claims, since I am not sure if this is just coincidental or some conflicts with other mods, in which I also use other mods along with it.

Oh, and using the S3RC my save file size has been reduced to 99.5 MB from 148MB just for information. No significant gameplay changes except for some hairs getting corrected from dead ancestral sims.

Welcome to the Error 12 and 13 club.

Now refer to this thread http://www.moreawesomethanyou.com/smf/index.php/topic,15623.0.html. Next time search first before making a new thread. Multiple threads just makes helping and learning from each other difficult and disorganized. Learn from the example of the Official Sims 3 thread, lots of them have exactly the same problem (but written differently) but gets no definite answer.

Just an update:

S3RC on save games does not really help in error 12s and 13s but it does correct weird and funky hairs of dead ancestors.

Also bloating up your town with sims and stuff as already known will cause error 13s, but upon correcting the error 13, there is chances of error 12 replacing it. So far not any of the commands I used before works against the error 12 that replaced error 13. Will re-verify this again tomorrow.

Prior to this happening, I noticed that the path finding AI of some sims are disabled. When I direct them to a door, they go straight to that direction and stop in front of a wall that is between the sim and the door. And visiting neighbors, the ring doorbell becomes inaccessible and only functional if you do it outside of the neighbor's lot. Succeeding in ringing the doorbell, the neighbor inside the house just keep doing what it has been doing ignoring the bell. I had similar experience two months before and it also ended up in an error 13 and then error 12.

I never thought of using the s3rc. It's worth trying.

I just re-read the description regarding the bloated saves s3rc can fix, it's possible it could work. If I remember correctly, a handful of my sims have thumbnails that does not belong to them. Probably this could correct it. I just used to let those sims die or execute them, probably they're still haunting in my game somewhere.

You're still the Greatest! Thanks, Pescado.

EDIT
Just read up on the Simselector Mod, I'm not sure if it was built using the Make Sim Selectable option on the EA Debug Interaction. So far, some sims in my game somehow does not respond well with that EA debug interaction.

Are you selecting the same sim all those time you use the Simselector before the error 12 appear?

Have you tried removing all the hacks / mods and Custom Contents as well as store items and just play the game vanilla? A patched game would be okay. Sometimes playing it without hacks will reveal what problem is causing the error 12s. Though in my case removing the hacks the game started going weird seemed like a nightmare. But that experience showed me what's really causing my game to bug.

Also, could you recall any mods that you removed before having this error problem? I tried Kolipoki's Plant roasts and links mod when I removed them days after, my sims started getting bugs. Do you have any similar incidents?

If you do have any hacks removed, maybe it is better to reinstall the game and only apply the patch and re-load your old save and play normally.

Another suggestion, if you have the time try going into every lot in the game and see if there are immovable graves inside or any weird stuff that you'll consider a bug. Try deleting those you deem irrelevant and problematic. It will not only reduce possible / potential error 12s but also help in error 13s. I mentioned immovable graves because some sims die inside the lot and the game failed to transfer it to the mausoleum, it will register to the game as default graves like Eric Darling's (crumplebottom) grave or the ones at the cemetery. For my game, the tombs at the Jones and Goth houses are movable but Eric Darling's isn't.

Lorea, perhap you could try these commands from Awesomemod and see what results you get:
1. Fixall - somehow sims get bugged after playing for more than 2-3 hours especially when the neighborhood has lots of history in it.
2. Towderelicts - Derelict cars clutters and just adds to the objects in your cache.
3. Resetallwants

Also try from the NRaas Supercomputer
1. Recover Lost Sims - Lost sims can cause error 12s
2. Recover Wandering Toddlers - Not sure if this also causes the errors but it's worth trying
3. Turn off stereos - just making sure.

If every result of these are clean (without any fixes made) and still encountering error 12s try
1. Destroyalltownies
2. Destroyallnpcs

Of course make a backup save before trying. If nothing works, perhaps it's a type of bug I haven't encountered yet. I may need a copy of your save game to experiment with.

In the meantime, if you say that you get the errors at the 3rd hour, since AM is set to autosave, maybe it would be best that you quit your game and reload it after the 2nd save. It will prolong your game for another 2 hours since the cache will get refreshed when you quit the game. The waiting time will be less of a problem than re-doing all the lost work.

Actually, that's my post over at the Sims 3 site, it's basically a summary of what I posted before. I'm still working on the error 12 and 13 problem.

My updates are a bit slow these days, I get rare error occurances after performing the debug commands I listed above. It would be helpful if you can help observe what weird and not-normal things that happen on your game. Sometimes seemingly unrelated stuff and minor bugs starts all these mess.

What I can identify right now is excessive cheating also causes the game to have this error. Setting all motives to static for a extended period causes some sim problems especially on the dreams, promises and wants department. I also found that it also affects some sim / lot description errors. Forcing the wrong opportunities via the debug interactions will also make bugged sims. Some mods and hacks when removed will also contribute. Moveobjects on unmovable graves caused many problems for me, that whenever a ghost gets spawned, I'll get error 12. (Maybe I'm just unlucky, or there is something else happening to the grave when I moved it, cannot tell right now.)

From what I gathered the game limits the allowable for each neighborhood cache at 1GB. So with more RAM you're still be limited to 1GB to play around with.

I've been thinking of copying the Sunset Valley.ObjectCache file and renaming the copy to Riverview.ObjectCache and probably also try again to bloat the dynamic caches to around 1GB then replace back the objectCache files and overstuff the whole town and see if the passive + dynamic cache stack or not.

Oh I forgot to mention, testing Jordi's resourcecachebudget setting of 90000 have improved lessening error 13s and textures and graphic details loads more faster. Just guessing that the textures and details may have been allocated to another cache.

Upon aging up her hair grew on her waist

The Invisible Man (Under the plumbob)

The Invisible Man's Tombstone (Only shadow is visible)

Siamese Twins. (This whole townie family has the same hair except for the mom, she might be undergoing chemotherapy)

1/2 The family is asking the kid what he wants to be when he grows up...

2/2  Lifetime wish = Become a registered sex offender

As far as I know, bad sim descriptions are the cause of Error 12. In my experience resetsim/resetworld works. Though corrupt objects could also theoretically cause Error 12 any the only solution is either to remove all the CCs and replace it one by one until you find the culprit or if you don;t have any CCs then try re-installing the game. In some reports the game cache does not install properly.

If you are brave enough to experiment, you can try the using all the commands I placed above.

Another thought is that there may be a possibility that the error 12 is caused by a dead sim. That I have not yet figured how to correct as of this moment.
    Resetsim and resetworld does not seem to work on these dead buggers.
    Resurrecting them then fixing then killing them again does not work either.
    Deleting urns and tombstones does not help. It just makes solving the problem harder. (so I'm waiting for someone to develop a deleted urn/tombstone re-spawing mod for this)
   

I forgot to mention in my previous post, The first time I did this type of maintenance, I used all these commands just to make sure all possible bugs are fixed.

Resetallwants and ResetDnP is best used for Error 13s

This is what I did to my game which helped. It may not be 100% effective since there are many factors causing the error 12s.
 
The commands can be done in random order. Try which ones works for you.

Use after starting a new loaded game.

Using Awesomemod:
1. Resetallwants
2. Cleanhouseholds all
3. Refreshtraits all
4. Purgegenetichair
5. Fixall
6. Fixagingstates
7. Purgereactions
8. Fixromances
9. Towderelicts on (sometimes this command does not work on some cars and you have to individually nuke stuck cars)
10. Resetworld
11. Destroyallnpcs (Some grim reaper hacks and outfits + 1.3 game update causes bugged reapers)
12. Destroyalltownies (optional) but sometimes the townies are bugged
13. ResetDnP all
14. Destroycorruptsims (so far this command always yield me 'zero' corrupt sims but better be safe)

Using NRaas Supercomputer
1. Recover Lost Sims
2. Recover Wandering Toddlers
3. Turn off stereos

Save

Quit and restart game.

Observe if performance and saving game improve. Try saving every 15 minutes (use Awesomemod autosave feature)

Another option, if this does not work, try re-installing the game. Redo the above commands and re-observe.

So far these seemed to fix 80% of my Error 12 problems. Again, the above does not solve all the error problems but it corrects some of it. When I first tried these commands it really surprised me how much bugs and errors I have collected over 3 months of playing. (hmm, probably there's a hidden EAxis skill, the 3rd type "Bug Collecting" classification.)

You can test adjusting the resoucecachebudget based on Jordi's findings http://www.moreawesomethanyou.com/smf/index.php/topic,16709.0.html somehow, I have not yet encountered an Error 13 after adjusting this value. I have been overloading the game with non EA CCs (hair, objects and stuff) and observe. So far everything is running fine.

Resetworld have seem to resolve my Error 12s. No aging dead persons messages and other obvious bugs that I have before. Will still test it out more.

You know, I have been looking for this command ever since I started having error 12s. Pescado did confirm its existence, though I did not push to get this command from him.

Thinking about it, if I got this command the easy way, I might not have persisted to understand the error's source.

Edit 10/01 Tried using "Resetworld" right after loading a saved game. The game paused for 30-40 seconds. Did not encounter any errors for the whole night. I will overload the game with CCs and other stuff and try again. I just hope this is the solution to the problem.

Found something new on error 12. The source of the error is also found in the cache. Something during gameplay gets corrupted and it is written in the cache. So unless the corrupted data gets refreshed/reset the error will persist and will refuse to let you load a previous saved game.

The only solution I can think of right now is someone developing an in-game cache refresh/reset command.

So far, Bigpooh's solution works for error 13. The first 2 steps can be skipped.

From my latest tests and observations, these are the common trends that is visible in my game for the errors.

ERROR 13
There is a limit for the game where there is a maximum number sims, objects and lots allowed for the world cache. Loading the game, starting positions and conditions are loaded into the cache initially so with a high number of sims and lots will reduce allowable cache space. Every additional actions/reactions of any sim in the hood will be logged into the cache. Also textures and graphic details are also recorded into the cache. In which some players reports lower error 13 instances with lower graphics detail.

My observation is that the game only purges items and unlocked wants and other stuff that's being cleaned up during 12am and 5am (perhaps there are other cleanup times that I do not know of). So basically stuff are not deleted becomes somewhat persistant until deleted and meanwhile eats up available resources. I believe saving is also recorded into the cache since my cache timestamps reflect the time where saving is in progress. It is possible that inadequate resources causes the post-save callback error (error 13)

After re-installing, I haven't tried adjusting the resoucecachebudget if it can in place store the texture and graphic detail data to lessen the load of the cache.

ERROR 12
So far, what I can determine here is a random data bug where the game randomly allows and disallows. It's very hard to guess whether there is a number of allowable bugs or there is a certain bug that the game actively screens. The bugs can range from sim descriptions, stuck object/sim bug, missing object/sim/texture (The "?" tiles in my game is a result of a failure load in textures, somehow the game forgets the textures (especially custom textures) and just replaces it with the "?" tiles.).

In all my attempts, an error 12 often couldn't be resolved except for a re-load of the game. Somewhere between the last save and the error 12 is a event that caused it. It could also be possible of an erroneous cache writing or data overlap that is related to error 13. It often did confuse me that reseting some lots replaces the error 13s to error 12s.


Aside from playing around with the resoucecachebudget, the solution seems beyond my abilities. If someone can confirm these findings and someone with better knowledge of the codes could thinker with it perhaps we can find a better and permanent solution for this problem until the next EP or update screws it up again.

I agree that sometimes a sim does get screwed up and when he/she dies or moves out, the game will become normal.

My current impression with the errors has something to do with the base game itself. Adding CCs and other stuff just accelerates the process. My objective is to try and isolate what's really causing these errors. Otherwise in the eventuality that  EP5 comes out, we'll be looking at a 1 GB save file with unresolved error saving problems (that is EA doesn't add more problems along the way, though it is certain that there will) the game will be unplayable to most of us having these error problems.

Upon my current situation with the game, the errors has a certain pattern that triggers it. I currently believe these are the triggers that starts the errors in my experience:

Error 12:
1. After re-installing the game, my common error 13s were replaced by error 12s. Since my population has greatly been reduced by the Awesomemod and the Unified Billing feature, it was more easy to track that there were sims disappearing and reappearing who never ages (they must have advance tickets to go on World Adventures).
2. My ghost having aging problems also. This caused me to delete my graveyard to prevent them from appearing.
3. My sim descriptions always gets damaged. Three days ago I was plagued with townies that has no traits, no favorites and obvious clones (from hair to clothes) of other townies, so many of them looked alike. Fixing that, Two days ago it was the attack of the invisible sims. And yesterday, it was townies when added to your family become un-selectable (their portait will appear on the family but cannot be accessed or selected (even with cheats)).
4. There is a new bug in my game, the Awesomemod "Nuke" option is gone. Since no one is complaining about it so I deduce that it has some problems with my game itself.

Error 13:
1. Aging states of sims. For some reason 85% of the time a sim ages on your play lot +/- 5 hours of the aging process will result to error 13
2. Adding new furnitures in a overly decorated house + the factor of playing the game for at least 20 real time minutes will also produce error 13. A newly loaded game will not have the error 13 assuming you are decorating the same items from the previous error 13 experience, adding a little bit more decorations, I get a 50/50 chance of it will error.
3. Whenever ghosts appear on my play lot the game, I'm sure to have error 13 when they leave.
4. Also noticing that world caches are accessed regardless of you playing that neighborhood or not at a point which I believe, you're computer's extra resources gets used up and the dynamic caches stop increasing in size. That's the time my error 13 shows up. There are times the dynamic caches will start increasing again, it did also stop the error 13 temporarily.

There are more that I cannot remember at of these moment, some I already posted earlier. I think isolating what causes this errors would be helpful on determining a solution.

Yes I forgot about this. To save time on testing, I'll try to focus more on the above mentioned conditions. Thanks.

In my point of view, what EA says as compatible is based on what configurations they have when they tested the game. Since there are many different OS, driver versions, hardwares and supporting softwares, the combinations are endless and there are sometime subtle incompatibilities. That produces unique and unexpected errors. I even had a experience that the motherboard chipset version was incompatible with my graphics card processor, all other programs, games worked well except for a single game whenever a cinematic would play the whole program will go crazy.

One thing that may be worth trying that may help is to re-install your game.

If you are playing Riverview, try not to turn on Sunset Valley and Likewise, the same if you're playing Sunset Valley. Maybe having both neighborhood caches active while playing is draining your pc's resources. So far this helped in my case.

The test for the vanilla game with no CCs added except for the patch, may take a while to bloat up the neighborhood. Without the awesomemod it will take double the effort since the vanilla game will delete random sims basically erasing them from the game like the "Destroyall..." command of the Awesomemod. Perhaps it's the game's way of cleaning up to avoid over bloating the save game. I need the patch because it will take even longer since the unpatch game deletes more sims randomly, the patch reduces the randomness of the deletion but it still randomly deletes sims.

Yes that's a good suggestion.

My main priority was to recover first my legacy save game. Cleaning almost all the major buggy sims, hence eliminating everybody in town leaving only 2 sims left (my legacy family), moved them to another lot and played the game (turning off Awesome Story Driver and the Unified Billing to repopulate the neighborhood and reduce homeless bums.) So far been testing it for a day, no error 12 or 13 on normal playing. I only got error 12 when I introduced sims from Riverview into the hood that are on my household bin. So far Riverview is still off and no caches from Riverview is generated.

So far my goal is complete for my legacy family (19 generations in all), Tomorrow I'll set up the configuration as to your suggestion and compare results.

My problem started a few weeks after the first patch was installed. It was when I removed a mod that I wasn't even using.

Sorry for any confusion, After re-installing the game. I immediately patched it and installed everything that the store offered (only store items, hair, sets, clothes ...) Most of my issues started when I added custom contents and mods, I figured since some of the other players are saying that they have this error issues even without mods or custom content, I'd start from there.

One of my first test was to re-use my old save game and see if there was an installation failure since my last install, or a mod may have inadvertently damaged some files in the game.

The other test I plan to do is set create a new town and set the aging to the shortest possible time and try to bulk up the town to the same level I have and compare the difference.

The second test was sort of postponed when I was welcomed with a bulk of bugs and errors that was not noticeable prior to the re-installation. So I'm right now trying to recover any salvageable part of the old game and slowly isolate the bugs and remove them. (I figured that posting my progress might help in case someone encounters the same problem, or get someone's experience in this problem for possible solutions)

For the mods I downloaded, yes I get random of custom contents buried into the files. There was even a mod that really emptied all the information of 2 of my sim's skills window. The tab and the skills are active but when you check the skill details the whole page is blank. (in TS2 there are some houses that contained lots of custom careers without any residents in them, that really screwed up my loading time to an hour per load.) as you can tell I haven't learned from that lesson.

I also failed to mention, in this new installation I haven't activated Riverview, so basically, the Worldcache folder has not been generated. My observation is that the Riverview cache is being accessed when you run the game, regardless if you are playing only Sunset Valley. It may be a memory hog that may contribute to error 13. Until the save errors in my previous save is corrected, I cannot yet determine if having the Riverview cache removed will help or not.

And Sorry if I may be rambling or not making some sense. Just tired and frustrated.